The present application is based on the Japanese Priority Application No. 2003-194584, filed on Jul. 9, 2003, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus forming a color image such as a copier, a printer, a facsimile machine or such in an electrophotographic type or an electrostatic recording type, a program applicable to such an image forming apparatus, and a positional error correction method applicable to such an image forming apparatus.
2. Description of the Relate Art
In the related art, a method for avoiding positional error which is error in mutual position in images of respective colors which should agree with each other to create a proper color image as a combination thereof otherwise causing color drift in a full-color image forming apparatus, is known. Specifically, for example, as one method, a series of toner marks are formed especially for the purpose of positional error detection.
Japanese Laid-open Patent Application No. 9-204087 discloses a method in which a plurality of types of marks for the detection are formed, by which information of periodic rotational variation of color registration drift is obtained. In this method, a plurality of sampling periods are prepared for the marks for the detection.
Japanese Laid-open Patent Application No. 11-102098 proposed by the present applicant discloses a configuration in which a detecting unit detecting positional error detection marks including lines along a main scan direction and those oblique with respect thereto includes slits in parallel to the respective marks, a light source part and a light receiving part.